The present invention relates to a locking device consisting of a bolt lock and key-actuated lock cylinder (18 or 77) in which the lock cylinder including a locking member (29 or 82) thereof is in coupling engagement with a bolt-actuation device, and can be removed from a bolt lock only by use of a key.
Such a locking device which is suitable for use on doors of lockers, is known from Austrian Patent No. 310 610. The bolt lock is fastened on the inside of the door while the lock cylinder passes through the door and can be actuated by a key which can be inserted from outside the door. When the bolt is in its retracted position, the key cannot be removed. It can be removed only after completion of the forward closing movement, which requires the insertion of a coin. If the user of the locker then loses the key, the locking device can be opened by a master key which is in the possession of a supervisor. If such a master key, however, comes into unauthorized hands, corresponding lockers can be opened and then closed again without leaving any trace. It is therefore difficult for the user of a locker to prove that he has been robbed. Also in the case of other locks the problem frequently arises that it is not possible to verify whether a lock cylinder has been actuated by a given key. If due to his absence, the owner of a house, for instance, turns over his key to a person to whom he allows access in case of an emergency, then he cannot determine after his return whether the key was actually used or not.